The invention relates to a circuit for calculating the value of a complex digital quantity.
In particular, the present invention relates to a circuit arrangement with digital circuits for calculating the value of a complex digital quantity x+iy of two digital values x and y as an approximation by means of a basic circuit.
In some digital-transmission systems using amplitude modulation, it is necessary in connection with the demodulation of quadrature signals to calculate the amplitude (value) EQU B=.sqroot.x.sup.2 +y.sup.2,
i.e., the value of the complex digital quantity x+iy.
Demodulation of quadature signals is necessary, for example, in AM stereo systems and in the arrangement disclosed in German OS No. 31 14 063.
The value B could be calculated electronically by squaring x and y and then extracting the root by known methods, e.g., with the aid of a table and/or by polynomial approximation. Another method would be to use logarithm tables.